The field to which the present invention relates is that generally known as electrical discharge machining, sometimes hereinafter referred to as "EDM," in which material is removed from an electrically conductive workpiece by the action of precisely controlled electrical gap discharges occurring between a tool electrode and the workpiece. A dielectric coolant fluid is circulated and recirculated through the gap, usually under pressure, throughout the machining operation. An electrode or workpiece servo feed system is used to provide relative movement and thus maintain an optimum gap spacing between the electrode and workpiece as the workpiece material is being removed. It is important in the process of electrical discharge machining that the machining power pulses provided to the gap be closely and precisely controllable in their on-off time and frequency to insure predictability and repeatability of results and to provide appropriate cutting action for the particular type of operation being carried on. For example, with a roughing type machining operation, relatively low frequency, high current magnitude pulses would be used for cutting. For a finishing type machining operation, relatively high frequency, low current magnitude pulses would be employed. Various types of pulse generators which have this capability and adjustability have been developed and are in current commercial use for electrical discharge machining.